KERMA Flashcards
What is KERMA
Kinetic energy released in the material
explain kerma
exponential decay of kerma with depth
most enegry released on surface
shape of CADD KV and kerma = identical but different things looked at
absolute dose is looking at where the dose is in tissue whereas kerma is looking at where energy is being released into tissue
when low energy hits surface - lots of scatter and secondary electrons
photon comes in and releases energy and gives it to electron
electrons move away from site of release because of KE present -> exponential decay seen on kerma
deposit energy at end of path.
scatter = no net movement
why does it allow for skin sparing
electrons move forward and deposit dose deeper into surface right at the end of track
why does the absorbed dose line corss and stay above kerma
area under absorbed dose curve has to equal to kerma.
Kerma has large area under it because its absorbed first so absorbed dose has to catch up
